Diagonal brace mounting for bulldozer blades



Aug. 21, 1962 R. w. LlCHTl 3,049,820

DIAGONAL BRACE MOUNTING FOR BULLDOZER BLADES Filed April ll, 1960 3Sheets-Sheet 1 IN V EN TOR.

Passer W. LICHTI BY g wrhzgiwxf ATTORNEYS R. w. LlCHTl 3,049,820DIAGONAL BRACE MOUNTING FOR BULLDOZER BLADES Aug. 21, 1962 5Sheets-Sheet 2 Filed April 11, 1960 INVENTOR. EOBEET W L/CHTI ATTORNEYSDIAGONAL BRACE MOUNTING FOR BULLDOZER BLADES Filed April 11, 1960 3Sheets-Sheet 3 C INVENTOR.

f Ease/2T 1M L/CHT/ ATTORNEYS 3,049,820 DIAGQNAL BRACE MOUNTING FORBULLDOZER BLADES Robert W. Lichti, Joliet, IiL, assignor to CaterpillarTractor (10., Peoria, IlL, a corporation of California Filed Apr. 11,1960, Ser. No. 21,501 Claims. (Cl. 37144) This invention relates tobulldozers and particularly to means for bracing bulldozer blades toprevent damage resulting in part from stresses which are set up when ablade is adjusted to its tilt position.

Many conventional bulldozers comprise a blade carried at the forwardends of push arms pivotally supported on a tractor to permit raising andlowering of the blade. Diagonal braces between the push arms and theback of the blade in a horizontal plane prevent sidewise movement of theblade. Tilt braces extend diagonally upwardly from the tops of the pusharms to the back of the blade to hold it erect and by varying the lengthof one or both tilt braces, the blade is tilted to enable it to providea sloping cut. Because of the system of bracing employed, this tiltingof the blade sets up stresses and particularly compressive stresses inthe diagonal braces which in turn impart bending forces to the pusharms. Because of these forces, push arms are often broken when a bladein tilt position is subjected to side thrust in operation.

It is the object of the present invention to provide an improvedmounting for bulldozer blades and particularly for the diagonal bracesthereof whereby excessive compressive forces are relieved when the bladeis tilted and whereby upon the imposition of side thrust, stresses whichtend to damage the push arms are equally distributed between thediagonal braces to prevent their concentration at one point on one ofthe push arms.

Further objects and advantages of the invention and the manner in whichit is carried into practice are made apparent in the followingspecification by reference to the accompanying drawings.

In the drawings:

FIG. 1 is a schematic view in plan of a tractor with a bulldozerembodying the present invention with the nature of forces imposed on thediagonal braces indicated by arrows;

FIG. 2 is a similar view indicating the distribution of forces which aredestructive under certain operating conditions;

FIG. 3 is a perspective view of a bulldozer blade embodying the presentinvention;

FIG. 4 is a perspective view of a portion of the structure illustratedin FIG. 3;

FIG. 5 is a perspective view similar to FIG. 3 illustratin g a modifiedform of the invention; and

FIG. 6 is a view like FIGS. 1 and 2 illustrating a conventionalbulldozer and indicating the direction of destructive forces underdifferent conditions.

In FIGS. 1 and 2 of the drawings, a tractor generally indicated at 10 isshown as provided with a bulldozer blade 11 which, as also illustratedin FIG. 3, is carried at the forward end of a pair of push arms 12. Attheir rearward ends, the push arms are connected in a conventionalmanner to the truck frames of the tractor as by ball and socket typejoints shown at 13. .The bulldozer blade is pivotally connected to theforward ends of the push arms as by hinge connections 15 and held in anerect position by braces which are called tilt braces shown at 16 and 17and the latter of which includes adjustable means as, for example, ahydraulic cylinder shown at 1-8 in FIG. 3. The tilt braces are connectedas by pivot pins and brackets 19 to the tops of the push arms and balland socket joints 20 to the back of the blade adjacent its upper edge. Apair ted Patent 0 of diagonal braces 22 and 23 extend between the innersides of the push arms to which they are pivotally connected withbrackets illustrated at 24 and these diagonal braces are, inconventional bulldozers, usually connected directly to the back of theblade by a ball and socket joint such as illustrated at 215 in FIG. 6 ofthe drawings which discloses a conventional bulldozer. Conventional liftjacks are shown at 26 as extending between the tractor and bulldozerblade to which they are connected as by pins in bracket -27 (see FIGS. 3and 5) fixed to the back of the blade.

Tilting of the blade, as for example toward the right, is accomplishedby lengthening the tilt brace 17 through the cylinder '18, fluid towhich is supplied in a conventional manner which, due to the bracingillustrated and described above, raises the left end of the blade aswell as the forward end of the push arm. This imposes stresses on thediagonal braces and the push arms which are indicated by arrows in FIG.6 of the drawings. Both diagonal braces are placed in compression asindicated by arrows a thus imposing a bending stress on each of the pusharms indicated in FIG. 6 on the right hand push arm by an arrow b asexerted outwardly on the push arm just behind the connection of thediagonal brace therewith. When this condition exists and a side thrustindicated by an arrow 0 is applied to one end of the bulldozer blade,the structure tends to collapse adding compressive stresses indicated byan arrow d to the right hand diagonal brace thus increasing the bendingstress represented by the arrow b and often resulting in breaking of theright hand push arm. Meanwhile the compression of the left hand diagonalbrace represented by arrow a has been relieved by the side thrust whichimparts tension to the diagonal brace as represented by the arrow e.

Through the present invention, the compressive stress in the diagonalbraces and the bending stress on the push arms is reduced and also thegreater compressive stress received by one diagonal brace is distributedto and therefore partially borne by the other diagonal brace. This isaccomplished as most clearly illustrated in FIG. 3 by connecting theforward ends of the diagonal braces 22 and 23 to opposite ends of atorsion bar 30, also shown in FIG. 4, through the medium of ball andsocket joints 31 in abutment members 32 rigidly secured as by welding orthe like to opposite ends of the torsion bar. This assembly is pivotallyconnected with the back of the bulldozer blade by pins which extendthrough upstanding ears 33 on the members 32 and brackets 34 secured tothe back of the bulldozer blade. This permits slight swinging movementof the torsion bar. Endwise movement thereof, that is movement in thedirection of its own axis is prevented by abutment blocks 35 secured tothe back of the blade and shims as indicated at 36 may be employed ifdesired for replacement on the occasion of wear at the abutting surfacesand to effect centering of the blade with'respect to the tractor.

With the construction above described, when the blade is tilted byactuation of the tilt cylinder 18, both diagonal braces tend to becompressed as represented by the arrows a in FIG. 1 but due to thepivotal support of the torsion bar assembly, it is permitted to rotateor swing slightly toward the blade, thus relieving the compressivestress and eliminating the application of excessive forces which tend tobend the push arms outwardly. When a side thrust is imparted to theblade, as represented by the arrow 0 in FIG. 2, whether or not the bladeis tilted the compressive stress of arrow a in FIG. 2 and the tensilestress of arrow e therein in the two diagonal braces are equalizedbecause the stress of each diagonal brace is transmitted to the otherthrough twisting action of the torsion bar 30 and the forces representedby the arrows b and f in FIG. 2

are also equalized to insure that each of the push arms supportsone-half of the load imposed by the side thrust.

A modified form of the invention is illustrated in FIG. 5 wherein atorsion bar shown at 30a is directly pivoted in brackets 34a secured tothe back of the bulldozer blade and lever arms 4d are fixed againstrotation at opposite ends of the torsion bar and carry sockets 41 toreceive the balls on the ends of the diagonal braces 22a and 23a. Inthis modification contact between the levers 4% and the brackets 34aprevents longitudinal movement of the torsion bar though it is capableof the rotational and twisting action referred to above.

I claim:

1. In a bulldozer blade mounting which comprises push arms secured tothe blade, tilt braces extending upwardly between the tops of the pusharms and the blade, and diagonal braces extending inwardly from theinner sides of the push arms to the blade and means to adjust the lengthof at least one of said tilt braces to effect tilting of the blade,means to reduce stresses set up in the mounting upon such tiltingincluding, a member pivotally supported from the blade adjacent the endof each diagonal brace and having a part adapted to swing to and awayfrom the blade and connections between the end of each brace and one ofsaid parts, and torsion means connecting said pivotally supportedmembers.

2. In a bulldozer blade mounting which comprises push arms secured tothe blade, tilt braces extending upwardly between the tops of the pusharms and the blade, and diagonal braces extending inwardly from theinner sides of the push arms to the blade and means to adjust the lengthof at least one of said tilt braces to effect tilting of the blade,means to reduce stresses set up in the mounting upon such tiltingincluding, a member pivotally supported from the blade adjacent theforward end of each diagonal brace and a ball and socket joint betweenthe end of each brace and one of said members, and torsion meansconnecting said pivo-tally supported members.

3. In a bulldozer blade mounting which comprises push arms secured tothe blade, tilt braces extending upwardly between the tops of the pusharms and the blade, and diagonal braces extending inwardly from theinner sides of the push arms to the blade and means to adjust the lengthof at least one of said tilt braces to effect tilting of the blade,means to reduce stresses set up in the mounting upon such tiltingincluding, a member pivotally supported from the blade adjacent theforward end of each diagonal brace and a ball and socket joint betweenthe end of each brace and one of said members and a torsion barconnecting said members.

4-. In combination with a bulldozer having the usual blade supportedforwardly of spaced push arms, tilt braces extending upwardly from thepush arms to the blade, and diagonal braces extending inwardly from thepush arms to the blade, means to reduce stresses set up in diagonalbraces and push arms upon tilting of the blade by varying the length ofa tilt brace comprising a torsion bar supported for swinging movementabout an axis parallel to the blade between the forward ends of thediagonal braces and a swivel connection between the forward ends of eachbrace and opposite ends of the torsion bar.

5. In combination with a bulldozer having the usual blade supportedforwardly of spaced push arms, tilt braces extending upwardly from thepush arms to the blade, and diagonal braces extending inwardly from thepush arms to the blade, means to reduce stresses set up in diagonalbraces and push arms upon tilting of the blade by varying the length ofa tilt brace comprising a torsion bar supported for swinging movementabout an axis parallel to the blade between the forward ends of thediagonal braces, a swivel connection between the forward ends of eachbrace and opposite ends of the torsion bar, and means to preventmovement of the torsion bar longitudinally of itself with respect to theblade.

References Cited in the tile of this patent UNITED STATES PATENTS was rA.

